{"product_id":"castair-automatic-alternator-relay-460v-mounted-alt460m","title":"Castair Automatic Alternator Relay 460V Mounted - ALT460M","description":"\u003cp\u003eThe \u003cstrong\u003eCastair ALT460M\u003c\/strong\u003e is the mounted-panel version of the 460-volt two-compressor alternator relay. It automatically manages lead\/lag operation between two compressors on three-phase 460V electrical service, alternating which unit runs as the primary each cycle to equalize operating hours across both machines. The M designation means the relay ships pre-installed in a panel enclosure — ready for wall mounting and terminal wiring without any enclosure fabrication or relay mounting work on site.\u003c\/p\u003e\n\n\u003cp\u003eThe 460V rating targets industrial and heavy commercial facilities: manufacturing plants, large fleet maintenance yards, major collision centers, and any operation running high-horsepower three-phase compressors. If your compressor motor nameplates read 460V (also sometimes labeled 440V or 480V depending on the installation — verify against your relay specifications), this is the correct voltage. The ALT460M is the finished, enclosed assembly version; the ALT460 is the relay-only version for integration into your own panel.\u003c\/p\u003e\n\n\u003ch2\u003eThe Real Case for an Alternator Relay in Industrial Settings\u003c\/h2\u003e\n\n\u003cp\u003eIn a high-demand industrial facility, two compressors sharing a header or storage tank represent a significant capital investment. A pair of industrial three-phase compressors can represent $10,000 to $30,000 or more depending on horsepower and type. Without an alternator relay, that investment tends to develop an expensive asymmetry: one machine runs constantly while the other sits mostly idle. The working machine wears out ahead of schedule. The idle machine's oil degrades. Maintenance schedules become guesswork. And when the primary fails, the backup is not in the condition you thought it was.\u003c\/p\u003e\n\n\u003cp\u003eThe ALT460M addresses this directly:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eEven Hour Distribution:\u003c\/strong\u003e The relay automatically swaps lead and lag designations after each pressure cycle. Over time, both machines accumulate equal operating hours, which means equal wear, equal maintenance schedules, and a backup machine that is actually ready when the primary needs service.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDuty Cycle Management:\u003c\/strong\u003e Industrial compressor manufacturers specify maximum duty cycles — maximum run time as a percentage of total time, or maximum continuous run minutes. In high-demand production environments, a single compressor can be pushed past those limits. The ALT460M shares the load across two units, keeping each within its rated duty cycle. This is directly relevant to warranty compliance for new compressors.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOperational Redundancy:\u003c\/strong\u003e A lag compressor that has been running regular hours is a reliable backup. A compressor that has been sitting idle for three months with degraded oil and no recent exercise is not. The ALT460M keeps both machines active and ready, making redundancy real rather than theoretical.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhy the Mounted Version (ALT460M) vs. the Relay-Only (ALT460)\u003c\/h2\u003e\n\n\u003cp\u003eBoth the ALT460 and ALT460M perform the same control function. The difference is the enclosure:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eChoose ALT460M if:\u003c\/strong\u003e You want a complete, self-contained installation. The enclosure is built, the relay is mounted, and you connect to labeled terminals. This is the faster installation path and produces a cleaner result, especially in environments where exposed relay components are not acceptable. It also means no guesswork about enclosure sizing or mounting hardware.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eChoose ALT460 if:\u003c\/strong\u003e You are integrating the relay into an existing control panel, junction box, or custom panel assembly. You supply and mount the enclosure. Lower purchase cost, more layout flexibility, appropriate when the electrician is building a multi-component control panel on site.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIn both cases:\u003c\/strong\u003e Installation must be performed by a licensed electrician. Three-phase 460V control wiring requires proper expertise.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eFeatures\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePre-Mounted Panel Assembly:\u003c\/strong\u003e Relay arrives installed in enclosure — mount to the wall, wire to terminals, and the installation is complete. No enclosure fabrication required.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e460V Three-Phase Rated:\u003c\/strong\u003e Correct for industrial 460V electrical systems. Do not install on 230V service — verify your compressor motor voltage and panel supply before ordering.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAutomatic Lead\/Lag Alternation:\u003c\/strong\u003e Switches lead\/lag designation between compressors each cycle without manual intervention. Hours distribute evenly across both machines automatically.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLag Compressor Start:\u003c\/strong\u003e Brings the second unit online automatically when demand exceeds the lead compressor's output. Both units run until pressure recovers, then lag shuts down first.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eEnclosed Panel Format:\u003c\/strong\u003e Enclosure protects relay from industrial shop environment — dust, moisture, and incidental contact. Appropriate for permanent installation in compressor rooms and mechanical spaces.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompatible with Castair Control Accessories:\u003c\/strong\u003e Works with Castair hour meters (HRM75 for electric, HRM50 for gas engines), time delays (TD100, 18-240V, 1-1023 seconds), and low oil controls (6304, 6304B) for a complete duplex compressor control system.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCastair Manufacturing:\u003c\/strong\u003e Built by Cast Air in Minnesota, a manufacturer with a focused product line around duplex and industrial compressor controls and systems.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eCastair ALT460M automatic alternator relay, pre-mounted in panel enclosure\u003c\/li\u003e\n  \u003cli\u003eManufacturer documentation and wiring diagram\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eInstallation by a licensed electrician is required. The ALT460M handles three-phase 460V line voltage and must be wired correctly. If you have questions about the installation, call us at 866-217-0063 before you begin.\u003c\/p\u003e\n\n\u003ch2\u003eAvailable Configurations — Full Matrix\u003c\/h2\u003e\n\n\u003cp\u003eCastair makes four alternator relay configurations to cover both voltage classes and both installation formats:\u003c\/p\u003e\n\n\u003ctable\u003e\n  \u003cthead\u003e\n    \u003ctr\u003e\n      \u003cth\u003eModel\u003c\/th\u003e\n      \u003cth\u003eVoltage\u003c\/th\u003e\n      \u003cth\u003eFormat\u003c\/th\u003e\n      \u003cth\u003ePrice\u003c\/th\u003e\n      \u003cth\u003eBest For\u003c\/th\u003e\n    \u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n      \u003ctd\u003e\u003cstrong\u003eALT230\u003c\/strong\u003e\u003c\/td\u003e\n      \u003ctd\u003e230V\u003c\/td\u003e\n      \u003ctd\u003eRelay only — you supply enclosure\u003c\/td\u003e\n      \u003ctd\u003e$398.86\u003c\/td\u003e\n      \u003ctd\u003e230V systems, integrating relay into existing panel or custom control cabinet\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003e\u003cstrong\u003eALT230M\u003c\/strong\u003e\u003c\/td\u003e\n      \u003ctd\u003e230V\u003c\/td\u003e\n      \u003ctd\u003eRelay pre-mounted in panel enclosure\u003c\/td\u003e\n      \u003ctd\u003eCall for pricing\u003c\/td\u003e\n      \u003ctd\u003e230V systems, clean permanent wall-mount installation without enclosure fabrication\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003e\u003cstrong\u003eALT460\u003c\/strong\u003e\u003c\/td\u003e\n      \u003ctd\u003e460V\u003c\/td\u003e\n      \u003ctd\u003eRelay only — you supply enclosure\u003c\/td\u003e\n      \u003ctd\u003e$398.86\u003c\/td\u003e\n      \u003ctd\u003e460V three-phase systems, integrating relay into existing panel or control cabinet\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003e\n\u003cstrong\u003eALT460M\u003c\/strong\u003e (this unit)\u003c\/td\u003e\n      \u003ctd\u003e460V\u003c\/td\u003e\n      \u003ctd\u003eRelay pre-mounted in panel enclosure\u003c\/td\u003e\n      \u003ctd\u003eCall for pricing\u003c\/td\u003e\n      \u003ctd\u003e460V three-phase systems, clean permanent wall-mount installation — relay arrives ready\u003c\/td\u003e\n    \u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cp\u003eThe voltage choice (230V vs. 460V) comes from your compressor motor nameplates and your electrical panel service. The format choice (relay-only vs. mounted) depends on your installation setup. Call 866-217-0063 to confirm the right unit before ordering — this is a common question and we can help you sort it out quickly.\u003c\/p\u003e\n\n\u003ch2\u003eWhen Does a Facility Need This vs. Stepping Up or Down\u003c\/h2\u003e\n\n\u003ch3\u003eThe ALT460M is the right choice if:\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eYou are running two compressors on 460V three-phase service with a shared air system or header\u003c\/li\u003e\n  \u003cli\u003eYou want a finished, enclosed panel assembly — relay arrives ready to mount and wire, no enclosure fabrication needed\u003c\/li\u003e\n  \u003cli\u003eYour installation environment requires enclosed electrical components — industrial mechanical rooms, dusty environments, areas with moisture, or anywhere exposed relay components are not acceptable\u003c\/li\u003e\n  \u003cli\u003eYou are replacing a failed alternator relay in an existing duplex system and want a clean, professional replacement\u003c\/li\u003e\n  \u003cli\u003eYou want both compressors exercised regularly so the backup is actually ready when the primary needs service\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eThe ALT460 (relay-only) is better if:\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eYou are building a custom control panel and need to integrate the relay alongside other components in your own enclosure\u003c\/li\u003e\n  \u003cli\u003eYour electrician supplies and mounts the enclosure as part of a larger panel build\u003c\/li\u003e\n  \u003cli\u003eYou want to minimize the component cost and handle the enclosure on your end\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eYou need the 230V version (ALT230 or ALT230M) if:\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eYour compressor motors run on 230V service — verify voltage on the motor nameplate before ordering\u003c\/li\u003e\n  \u003cli\u003eConnecting a 230V relay to a 460V circuit is a wiring error. Verify motor voltage and panel supply before ordering anything.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eYou do not need an alternator relay if:\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eYou have only one compressor — this is specifically a two-compressor control\u003c\/li\u003e\n  \u003cli\u003eYour two compressors are on completely independent systems with no shared load — though equal wear and regular exercise of both units is still the correct maintenance approach\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eModel:\u003c\/strong\u003e ALT460M\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e ALT460M\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Cast Air (Castair), Minnesota\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVoltage:\u003c\/strong\u003e 460 Volt (three-phase)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Two-compressor automatic alternation (lead\/lag control)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFormat:\u003c\/strong\u003e Relay pre-mounted in panel enclosure\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompatible Accessories:\u003c\/strong\u003e HRM75 (hour meter 24-277V), HRM50 (hour meter for gas engines), TD100 (time delay 18-240V, 1-1023 seconds), 6304 (low oil control), 6304B (float switch for low oil)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePrice:\u003c\/strong\u003e Call for current pricing and availability\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDimensions\/Weight:\u003c\/strong\u003e Contact us to confirm shipping dimensions\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h2\u003e\n\u003cp\u003eAir Compressor Factory Direct has specialized in compressed air systems and components since 2016. We carry the complete Castair control accessory line and understand how these components fit into real duplex compressor installations. When you call about the ALT460M, you talk to someone who can help you confirm your voltage requirement, understand the difference between the relay-only and mounted versions, and make sure what you order matches your actual installation before it ships.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFree Shipping:\u003c\/strong\u003e On qualifying orders — confirm at checkout or by phone\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFree Technical Support:\u003c\/strong\u003e Call 866-217-0063 before or after purchase with installation or specification questions\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFull Manufacturer Warranty:\u003c\/strong\u003e All Castair components covered under manufacturer warranty — we handle warranty issues directly\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHonest Guidance:\u003c\/strong\u003e If the ALT460M is not the right unit for your installation, we will tell you that before the order ships\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSpecialist Focus:\u003c\/strong\u003e Compressed air systems and components are our core business. Castair controls are part of our standard inventory and we know the product line well.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003eCall 866-217-0063 for quick answers and help!\u003c\/strong\u003e\u003c\/p\u003e","brand":"Cast Air","offers":[{"title":"Default Title","offer_id":53342514053333,"sku":"ALT460M","price":1160.14,"currency_code":"USD","in_stock":true}],"url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-automatic-alternator-relay-460v-mounted-alt460m","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}